1. Field of the Invention
This invention relates to a multi-disc friction brake and, more specifically, to such a brake which includes an actuation piston and bore configuration which is simple and less expensive to provide.
2. Description of the Prior Art
There have heretofore been utilized a number of friction brakes which employ a plurality of relatively rotating friction discs and a means for applying compressive forces therebetween to produce the braking action. Some such friction brakes as those disclosed in U.S. Pat. Nos. 3,927,737; 3,941,219; and 4,146,116, utilize a circular actuation piston which has a cross-section at one side thereof which is generally L-shaped. Other brake configurations, such as those disclosed in U.S. Pat. Nos. 3,132,724 and 3,198,295, use a circular piston which is generally annular. Still other friction brakes, such as those disclosed in U.S. Pat. Nos. 3,081,842; 3,301,359; and 4,173,269, employ actuation pistons which have at one side thereof a generally T-shaped cross-section.
While the actuation piston devices in each of these friction brakes include a number of features which are quite different, there remains a common problem of manufacturing tolerances and general engineering manufacturing instructions in the formation of each which contributes significantly to the overall expense and complexity of manufacturing these brakes. In general, their manufacture includes a common concern for the tolerances of various diameters, the tolerances regarding concentricity of various surfaces, the smoothness of various surfaces during final machining and the tolerances and dimensions of piston or quad ring grooves formed in the surfaces.